{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,20]],"date-time":"2026-02-20T23:06:49Z","timestamp":1771628809598,"version":"3.50.1"},"reference-count":28,"publisher":"SAGE Publications","issue":"2","license":[{"start":{"date-parts":[[1981,6,1]],"date-time":"1981-06-01T00:00:00Z","timestamp":360201600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Cereb Blood Flow Metab"],"published-print":{"date-parts":[[1981,6]]},"abstract":"<jats:p> Changes in extracellular ion activities were measured during partial ischaemia of the cerebral cortex of primates anaesthetised with \u03b1-chloralose. Triple-barrelled, double-ion-sensitive microelectrodes were used to measure the extracellular potassium (K<jats:sub>e<\/jats:sub>) and calcium (Ca<jats:sub>e<\/jats:sub>) activity at the same point simultaneously. The ion changes were related to local cerebral blood flow, and it was shown that at a blood flow of approximately 10 ml 100 g<jats:sup>\u22121<\/jats:sup> min<jats:sup>\u22121<\/jats:sup>, there is a threshold below which ion homeostasis is disturbed. This is associated with a dramatic rise in K<jats:sub>e<\/jats:sub> and fall in Ca<jats:sub>e<\/jats:sub>. Ca<jats:sub>e<\/jats:sub> falls from a normal value of 1.31 \u00b1 0.1 mm to approximately 0.28 mm in densely ischaemic tissue. In ischaemia, K<jats:sub>e<\/jats:sub> reaches 13.4 \u00b1 3.8 mm before Ca<jats:sub>e<\/jats:sub> begins to fall. The fall in Ca<jats:sub>e<\/jats:sub>, although related to reduced blood flow, is closely associated with and follows the rise in K<jats:sub>e<\/jats:sub>. The change in Ca<jats:sub>e<\/jats:sub> is probably due to an increase in membrane permeability, as a result of either depolarisation or a critical lowering of cellular energy reserves. <\/jats:p>","DOI":"10.1038\/jcbfm.1981.21","type":"journal-article","created":{"date-parts":[[2011,4,7]],"date-time":"2011-04-07T16:00:25Z","timestamp":1302192025000},"page":"203-209","source":"Crossref","is-referenced-by-count":285,"title":["Changes in Extracellular Calcium Activity in Cerebral Ischaemia"],"prefix":"10.1177","volume":"1","author":[{"given":"Robert J.","family":"Harris","sequence":"first","affiliation":[{"name":"Gough Cooper Department of Neurological Surgery, Institute of Neurology, National Hospital, Queen Square, London, England"}]},{"given":"Lindsay","family":"Symon","sequence":"additional","affiliation":[{"name":"Gough Cooper Department of Neurological Surgery, Institute of Neurology, National Hospital, Queen Square, London, England"}]},{"given":"Neil M.","family":"Branston","sequence":"additional","affiliation":[{"name":"Gough Cooper Department of Neurological Surgery, Institute of Neurology, National Hospital, Queen Square, London, England"}]},{"given":"Muzaffer","family":"Bayhan","sequence":"additional","affiliation":[{"name":"Gough Cooper Department of Neurological Surgery, Institute of Neurology, National Hospital, Queen Square, London, England"}]}],"member":"179","published-online":{"date-parts":[[1981,6,1]]},"reference":[{"key":"bibr1-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1016\/0014-4886(71)90224-X"},{"key":"bibr2-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1161\/01.STR.8.1.51"},{"key":"bibr3-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1971.sp009641"},{"key":"bibr4-jcbfm.1981.21","first-page":"361","volume":"4","author":"Boysen G.","year":"1973","journal-title":"Stroke"},{"key":"bibr5-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1016\/0014-4886(74)90112-5"},{"key":"bibr6-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1016\/0022-510X(77)90014-4"},{"key":"bibr7-jcbfm.1981.21","first-page":"81P","volume":"275","author":"Branston N.M.","year":"1978","journal-title":"J Physiol (London)"},{"key":"bibr8-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1111\/j.1748-1716.1980.tb06544.x"},{"key":"bibr9-jcbfm.1981.21","first-page":"3P","volume":"312","author":"Harris R.J.","year":"1981","journal-title":"J Physiol (London)"},{"key":"bibr10-jcbfm.1981.21","first-page":"3","volume-title":"Cerebral Vascular Disease, Vol. 3, Proceedings of the 10th Salzburg Conference on Cerebral Vascular Disease","author":"Hass W.","year":"1981"},{"key":"bibr11-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-2828(77)80357-X"},{"key":"bibr12-jcbfm.1981.21","first-page":"14","volume-title":"Blood Flow and Metabolism in the Brain","author":"Heiss W-D","year":"1975"},{"key":"bibr13-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1161\/01.STR.8.1.77"},{"key":"bibr14-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1970.sp009095"},{"key":"bibr15-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1016\/0306-4522(78)90122-7"},{"key":"bibr16-jcbfm.1981.21","first-page":"5.8","volume-title":"Cerebral Function, Metabolism and Circulation","author":"Morawetz R.B.","year":"1977"},{"key":"bibr17-jcbfm.1981.21","first-page":"177","volume":"18","author":"Nicholson C.","year":"1980","journal-title":"Neurosci Res Prog Bull"},{"key":"bibr18-jcbfm.1981.21","first-page":"204","volume":"30","author":"Oehme M.","year":"1976","journal-title":"Chimia"},{"key":"bibr19-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1161\/01.STR.4.4.556"},{"key":"bibr20-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1126\/science.386513"},{"key":"bibr21-jcbfm.1981.21","first-page":"417","volume":"67","author":"Shen A.C.","year":"1972","journal-title":"Am J Pathol"},{"key":"bibr22-jcbfm.1981.21","first-page":"441","volume":"67","author":"Shen A.C.","year":"1972","journal-title":"Am J Pathol"},{"key":"bibr23-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1161\/01.RES.28.4.426"},{"key":"bibr24-jcbfm.1981.21","first-page":"199","volume-title":"Advances in Neurology, Vol 10: Primate Models of Neurological Disorders","author":"Symon L.","year":"1975"},{"key":"bibr25-jcbfm.1981.21","first-page":"165","volume-title":"The Cerebral Vessel Wall","author":"Symon L.","year":"1976"},{"key":"bibr26-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1161\/01.STR.5.3.355"},{"key":"bibr27-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1977.sp012046"},{"key":"bibr28-jcbfm.1981.21","doi-asserted-by":"publisher","DOI":"10.1038\/211646a0"}],"container-title":["Journal of Cerebral Blood Flow &amp; 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